The present invention relates to antimicrobial and anti-fouling catechol-containing polycarbonates for medical applications, and more specifically, to silicone catheter materials having antimicrobial and antifouling surface layers.
Nosocomial infections are one of the leading causes of death in the USA. Infections caused by medical devices, especially intravascular and urinary catheters, are major challenges in hospitals. Various catheter coating methods have been studied to prevent catheter-associated infections. However, it is difficult to obtain an effective and facile coating without elevating the toxicity of the catheter surfaces. For example, the coating of silver nanoparticles on catheters was reported to inhibit the adhesion of Staphylococcus aureus (S. aureus), while accelerating coagulation of contacted blood. As another example, hydrophobic drugs were applied to catheter surfaces using layer-by-layer techniques to generate antibacterial and antifouling catheter surfaces. Coatings of hydrophilic polyacrylamide and cationic 3-(trimethoxysilyl)-propyldimethyloctadecylammonium chloride on silicone rubber were also reported to prevent bacterial fouling. However, these techniques usually require multiple steps (e.g., surface hydrophilization, aminosilanization, chemical grafting, and/or polymerization) that increase production cost.
Poly(ethylene glycol) (PEG) has been of great interest in the development of antifouling coatings due to its hydrophilicity and nontoxicity. However, antifouling performance of PEG coatings decrease over time because PEG does not kill bacteria.
Recently, a two-step antibacterial and antifouling coating on a catheter surface was prepared by 1) forming a reactive polydopamine layer on the catheter surface and 2) reacting a diblock copolymer containing a thiol-functionalized PEG and cationic amphiphilic polycarbonate with the polydopamine layer via the thiol group on the distal end of the PEG chain. This coating successfully eradicated Staphylococcus aureus (S. aureus) in solution, prevented bacterial fouling on the catheter surface, and exhibited blood compatibility. However, this coating failed to kill and prevent fouling of Gram-negative bacteria such as Escherichia coli (E. coli), which often cause intravascular and urinary catheters-associated infections.
Therefore, a pressing need exists to develop more effective antimicrobial and antifouling coatings on silicone rubber materials for the prevention of CAIs.